Chromable monoazo dyestuffs



United States Patent CHROMABLE MONQAZO DYESTUFFS Werner Kuster and Guido Schetty, Basel, Switzerland, assignors to J. R. Geigy A. G., Basel, Switzerland, :1 Swiss firm No Drawing. Application March 16, 1953, Serial No. 342,712

Claims priority, application Switzerland March 23, 1952 5 Claims. or. 260-151) The present invention concerns the production of monoazo dyestuffs which have no sulphonic acid groups and the attainment of fast, chromium-containing dyeings on wool and on fibers similar thereto under conditions which do not injure the fibres. It also concerns the production of complex chromium compounds of the monoazo dyestuffs in substance.

It has been found that by coupling in an alkaline medium a diazotised 6-nitro-4-alkyl-2-amino-l-hydroxybenzene compound, the alkyl radical of which contains from 4-8 carbon atoms and which may also be cyclo-aliphatic, with l-hydroxynaphthalene-ir.o-disulphonic acid amide, new, valuable monoa'zo dyestuffs which contain no sulphonic acid groups are obtained of the general formula:

OH OH Alkyl These dyestuffs are distinguished by an excellent drawing power on to wool and fibres similar thereto from a neutral to weakly acid bath both when they do not contain any metal and also in the form of their complex chromium compounds. They are suitable therefore, for the attainment of blue shades on wool which have very good light and wet fastness properties both with the salts of hexavalent chromium when they contain no metal and also in the form of their complex chromium compounds. From a neutral to weakly acid bath, if desired in the presence of ammonium salts of organic and inorganic acids, the chromium-containing dyestuffs draw on to fibres similar to wool such as silk, casein fibres, synthetic polyamide and polyurethane fibres. For example, 6-nitro-4-tert. butyl-Z- amino-l-hydroxybenzene, 6-nitro-4-tert. amyl-Z-amino-lhydroxybenzene, 6-nitro-4-cyclohexyl-Z-amino-l-hydroxybenzene or 6-nitro-4-di-isobutyl 2 amino-l-hydroxybenzene may be employed as diazo components. These compounds are obtained, for example, by dinitration of the corresponding p-alkylphenols and reduction of only 1 nitro group to the amino group, e. g. with alkali sulphide or hydrogen sulphite in an aqueous organic or, for example, an aqueous alcoholic solution or suspension. As is usual, diazotisation is performed in the cold with sodium nitrate in a mineral acid solution or suspension and the coupling with the 1-hydroxynaphthalene-3.6-disulphonic acid amide is performed in an aqueous alkaline solution.

Various methods are known for the production of the complex chromium compounds in substance, e. g. treatment of the dyestufi's with aqueous solutions of the salts of trivalent chromium at a raised temperature in organic,

dyestufi molecules is particularly advantageous; it is expedient to use an excess of chroming agent. The alkali salts of the complex chromium compounds, which are obtained by salting out and drying, are dark powders which dissolve in water with a blue colour. It is expedient to mix them before using them for dyeing with anion active dispersing agents and inorganic salts which have an alkaline reaction such as trisodium phosphate. They dye wool in very level blue shades which are fast to light and wet treatments, from a neutral to weakly acid bath which may contain ammonium salts of organic or inorganic acids such as ammonium acetate or sulphate. The new complex chromium compounds form a valuable addition to the group of chromium-containing wool dyestuffs which can be dyed from a neutral to weakly acid bath. Both in their metal-free state and also in the form of their complex chromium compounds, they are distinguished from known similar products by their improved drawing power on to wool from a neutral to weakly acid bath.

The following examples illustrate the invention without limiting it in any way. The parts are given as parts by weight and the temperatures are in degrees centigrade.

Example 1 22.4 parts of 6-nitro-4-tert. amyl-Z-amino-l-hydroxybenzene with 4 parts of sodium hydroxide are dissolved in 200 parts of water, 6.9 parts of sodium nitrite in 35 parts of water are added and this mixture is added dropwise at a temperature not exceeding 3 to 25 parts by volume of concentrated hydrochloric acid and 100 parts of water. A yellowish-green suspension of the diazo compound is obtained. On completion of the diazotisation, the acidity of the diazo suspension is neutralized'with sodium 'bicarbonate until there is a neutral reaction to Congo red paper, after which a solution of 30.5 parts of 1.3.6-naphtholdisulphamide (M. P. 302-304") and 12 parts of sodium hydroxide in 300 parts of water of a temperature of 0-3 is added. After adding 100 parts of pyridine and 10 parts of 25% ammonia, the temperature is kept overnight at 0-3". The dyestuft is then precipitated with 40 parts of sodium chloride, filtered off and washed with 2.5

sodium chloride solution. When dry, it forms a dark blue powder which dissolves in water with a blue, and in concentrated sulphuric acid with a red-violet colour.

For use in the aiter-chroming or in the single bath chroming method, it is advantageous to mix the product with about 10% of calcined soda ash and 5% of a dispersing agent. The dyestufi dyes wool from an acid bath a red-violet shade which changes on after-chroming to blue. When dyed according to the single bath chroming process without or with the slight addition of acid, reddish-blue dyeings of equal shades and strengths are obtained from a completely exhausted bath. The dyeings have very good wet and light fastness properties.

Very similar dyestufis are obtained if, in the above example, the diazo component is replaced by 21.5 parts of 6-nitro-4-tert. butyl-Z-amino-l-hydroxybenzene, 24 parts of 6-n1tro-4-cyclohexyl-2-amino-l-hydroxybenzene or 26.6 parts of 6-nitro-4-di-isobutyl (octyl)-2-amino-1-hydroxybenzene. These dyestutfs are also excellently suitable for dyeing according to the single bath chroming process.

The dyestuff produced according to the method described above can be chromed as follows:

The filter cake of the dyestufi is pasted in 1000 parts of water and 10 parts of 25 ammonia, 100 parts by volume of a solution of ammonium disalicylate chromiate (containing 3% of chromium) are added and the whole is heated at 100 for 6-10 hours. After adding parts of sodium chloride, the dyestuii is filtered oii at 7080 and washed with a 5% sodium chloride solution and dried. The chromium complex dyestulf so obtained is a dark blue powder which dissolves in hot water with a blue and in concentrated sulfuric acid with a violet colour. The product, which for use is advantageously mixed with 20% of a dispersing agent and 20% of sodium carbonate, dyes wool a blue shade from a neutral and from a weakly acid bath. The dyeing has very good fastness to wetness and light.

The monoazo dyestuffs obtained from 6-nitro-4-tert. butyl-2-amino-l-hydroxybenzene, 6-nitro-4-cyclohexy1-2- amino-l-hydroxybenzene or 6-nitro-4-di-isobutyl-2-aminol-hydroxybenzene and l.3.6-naphtholdisulphamide can be converted into their chromium complexes in the same way. Products are then obtained which are very similar to that described in detail above. In particular, they have the valuable property of dyeing wool from a weakly acid or neutral bath in equal shades and strengths, which dyeings have very good fastness to wetness and light.

Example 2 10 parts of wool are entered at 50 into a dyebath containing 1 part of anhydrous sodium sulphate, 0.2 part of sodium monochromate, 0.3 part of ammonium sulphate and 0.2 part of the unchromed dyestufi according to Example l in 400 parts of water. The bath is brought to the boil and kept boiling for 1 hour to develop the shade. The wool, which has been dyed blue is rinsed and dried.

Example 3 OH I H OzN N=N H N 0 2S 8 O zNHa wherein R represents a saturated hydrocarbon radical with from 4 to 8 carbon atoms and (b) the chromium complexes of said dyestuffs containing one chromium atom in complex linkage with two molecules of dyestuif.

2. The complex chromium compound containing one chromium atom in complex linkage with two molecules of a monoazo dyestutf having the formula:

3. The complex chromium compound containing one chromium atom in complex linkage with two molecules of a monoazo dyestuflf having the formula:

OH OH OzN- N N HgNOzS SO ZNH:

4. The complex chromium compound containing one chromium atom in complex linkage with two molecules of a monoazo dyestuff having the formula:

OH OH O 2N N N HzNOzs SO2NHI CH1 OH:

5. The complex chromium compound containing one chromium atom in complex linkage with two molecules of a monoazo dyestufi having the formula:

OH OH O2N N=N HzNOaS 302N111 HaC- CHa mo- -CH;

References Cited in the file of this patent UNITED STATES PATENTS 1,903,600 Schweitzer Apr. 11, 1933 2,633,463 Kuster Mar. 31, 1953 

1. A DYESTUFF SELECTED FROM THE CLASS CONSISTING OF (A) THE MONOAZO DYESTUFFS HAVING THE FORMULA: 